Electronic apparatus and control method of electronic apparatus

ABSTRACT

An electronic apparatus includes a power source, a power monitoring unit configured to monitor an output voltage output from the power source, an acceptance unit configured to accept a user operation to turn off the electronic apparatus, and an execution unit configured to operate using power output from the power source, execute shutdown processing in response to the user operation accepted through the acceptance unit, and execute the shutdown processing when the output voltage monitored by the power monitoring unit is lower than a threshold voltage. The threshold voltage is higher than a guaranteed operation voltage of the execution unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. patent applicationSer. No. 16/843,776 filed Apr. 8, 2020, which claims priority benefit ofJapanese Application No. 2019-077389 filed Apr. 15, 2019. Thedisclosures of the above-named applications are hereby incorporated byreference herein in their entireties.

BACKGROUND Field

The present disclosure relates to an electronic apparatus that executesshutdown processing and a control method of the electronic apparatus.

Description of the Related Art

In a conventional image processing apparatus, such as a printer, afacsimile machine, or a copy machine, power output from a power sourceis supplied to each load of the image processing apparatus. The powersource outputs a relatively low voltage to be applied to, for example, acentral processing unit (CPU) and a memory, and a relatively highvoltage to be applied to, for example, a printer unit and a facsimileunit, of the image processing apparatus.

When devices having different operating voltages are supplied with powerin this manner, reduction of a voltage output from the power source dueto, for example, turning-OFF of a power switch for a short period oftime resulting in an instantaneous interruption of the supplied power,can cause the printer unit and the facsimile unit that operate at arelatively high voltage to be inoperable. In such circumstances, onlydevices that can operate at a relatively low voltage, such as the CPUand the memory, may be operable.

Japanese Patent Application Laid-Open No. 2009-76155 discusses atechnique for securely turning off a hard disk to prevent destruction ofthe hard disk when an instantaneous interruption of power supplied bythe power source is detected.

Even if an output voltage from the power source is reduced, the outputvoltage may be recovered to a normal range in some cases. According toJapanese Patent Application Laid-Open No. 2009-76155, an image formingapparatus cannot be activated, even if the output voltage from the powersource is recovered, unless a user operates a power switch.

SUMMARY

Various embodiments of the present disclosure are directed to atechnique capable of, even if an output voltage from a power source isreduced, shifting an electronic apparatus to a power-OFF mode afterexecuting shutdown processing of the electronic apparatus, and further,automatically activating the electronic apparatus when the outputvoltage from the power source is recovered.

According to various embodiments of the present disclosure, anelectronic apparatus includes a power source, a power monitoring unitconfigured to monitor an output voltage from the power source, anacceptance unit configured to accept a user operation to turn off theelectronic apparatus, and an execution unit configured to operate usingpower output from the power source, execute shutdown processing based onthe user operation accepted by the acceptance unit, and execute theshutdown processing when the output voltage monitored by the powermonitoring unit is lower than a threshold voltage. The threshold voltageis higher than a guaranteed operation voltage of the execution unit.

Further features will become apparent from the following description ofexample embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically illustrating an image formingapparatus according to a first embodiment.

FIG. 2 is a block diagram illustrating details of a controller unitaccording to the first embodiment.

FIG. 3 is a block diagram illustrating a power source system of theimage forming apparatus according to the first embodiment.

FIG. 4 is a timing chart illustrating operations performed when a powerswitch is turned ON according to the first embodiment.

FIG. 5 is a timing chart illustrating operations performed when thepower switch is turned OFF according to the first embodiment.

FIG. 6 is a timing chart illustrating operations performed when anoutput voltage from a standby power source is reduced and subsequentlythe output voltage is recovered.

FIG. 7 is a block diagram illustrating a power source system of an imageforming apparatus according to a second embodiment.

DESCRIPTION OF THE EMBODIMENTS

Various embodiments to implement the present disclosure will bedescribed with reference to the accompanying drawings. An image formingapparatus having a printing function and a scanner function will bedescribed as one example of an electronic apparatus. The image formingapparatus can shift into a normal power mode, a sleep mode, and apower-OFF mode. The normal power mode corresponds to a state 0 (S0) ofAdvanced Configuration and Power Interface (ACPI), the sleep modecorresponds to a state 3 (S3) of the ACPI, and the power-OFF modecorresponds to a state 5 (S5) of the ACPI. The image forming apparatusmay shift into a hibernation state corresponding to a state 4 (S4) ofthe ACPI.

<Overall Configuration of Image forming Apparatus>

FIG. 1 is a block diagram schematically illustrating an image formingapparatus according to a first embodiment. An image forming apparatus 1includes a power source unit 101, a controller unit 102, a printer unit103, and a scanner unit 104. Further, the image forming apparatus 1includes a power switch 105, a switch 106, a switch 107, and analternating-current (AC) plug 100. The power switch 105 is a mechanicalrelay switch and is turned ON/OFF by a user operation. The power switch105 is a main power switch of the image forming apparatus 1. The scannerunit 104 reads an original document image optically and converts theread image into digital image data. The printer unit 103 forms an imageon a sheet-like recording medium (paper) according to anelectrophotographic method. The printer unit 103 only needs to form animage on the sheet-like recording medium and its recording method is notlimited to the electrophotographic method. More specifically, therecording method of the printer unit 103 may be an ink-jet method or athermal transfer method. The controller unit 102 controls the entireimage forming apparatus 1. The controller unit 102 controls the printerunit 103 and the scanner unit 104. The controller unit 102, for example,controls the scanner unit 104 to read the original document image inresponse to a copy instruction from a user. The controller unit 102receives digital image data output from the scanner unit 104, executespredetermined image processing, and outputs digital image data that hasundergone the image processing to the printer unit 103. Subsequently,the controller unit 102 controls the printer unit 103 to form an imageon the recording medium. The power source unit 101 receives AC powerfrom the AC plug 100 plugged in an outlet outside the apparatus andgenerates direct-current (DC) power. The power source unit 101 suppliespredetermined power to the controller unit 102, the printer unit 103,and the scanner unit 104. The power source unit 101 generates a DCvoltage of 12 V and a DC voltage of 24 V. The voltages generated by thepower source unit 101 are not limited to 12 V and 14 V. The power sourceunit 101 may generate, for example, a voltage of 5 V and a voltage of 24V. The power source unit 101 changes an operation status in the powersource unit 101 in response to an activation signal 113 output from thecontroller unit 102. The switch 106 is turned ON/OFF depending on apower source control signal 114 for the printer unit output from thecontroller unit 102. With this operation, supply of power is stopped tothe printer unit 103 or power is supplied to the printer unit 103. Theswitch 107 is turned ON/OFF depending on a power source control signal115 for the scanner unit output from the controller unit 102. Thisoperation stops supply of power to the scanner unit 104 or suppliespower to the scanner unit 104.

<Configuration of Controller Unit>

FIG. 2 is a block diagram illustrating details of the controller unitaccording to the first embodiment.

The controller unit 102 includes a central processing unit (CPU) 200, animage processing unit 201, a power control unit 202, an operation unit203, and a random access memory (RAM) 204. The controller unit 102further includes a read-only memory (ROM) 208, a hard disk drive (HDD)206, an option unit 205, and a network control unit 207. The CPU 200 iscommunicably connected to each unit of the controller unit 102. The CPU200, for example, performs control of peripheral devices of the CPU 200and circuits, and arithmetic processing of data. For example, the CPU200 interprets image data (e.g., page description language (PDL) data)received by the network control unit 207 from an external apparatus, andproduces bitmap data.

The network control unit 207 communicates with the external apparatusthrough a local area network (LAN). The network control unit 207receives the image data (e.g., PDL data) from the external apparatusthrough the LAN. The network control unit 207 transmits, for example,image data stored in the image forming apparatus 1, setting informationset to the image forming apparatus 1, device information of the imageforming apparatus 1, consumable item information regarding consumableproducts used in the image forming apparatus 1.

The image processing unit 201 performs image processing such as screenprocessing on the bitmap data generated by the CPU 200. With thisprocessing, print data is generated.

The power control unit 202 is composed of, for example, a complexprogrammable logic device (CPLD). The power control unit 202 controlspower supply/stop to each unit of the image forming apparatus 1. Whilethe power control unit 202 according to the first embodiment is composedof the CPLD, the power control unit 202 may be composed of a CPU and amemory to control the power supply/stop to each unit of the imageforming apparatus 1 by the CPU executing a program.

The operation unit 203 is provided with an input unit for the userinputting various operations, and a display unit to display variouskinds of information. The input unit is a hardware key or a touchsensor.

The CPU 200 loads a program for the controller unit 102 stored in theROM 208 into the RAM 204 and executes the program. The RAM 204, which isa main memory, stores variables in the program and data transmittedthrough dynamic memory access (hereinafter referred to as DMA) from eachunit. The HDD 206 stores various programs (e.g., operating system)required to operate the image forming apparatus 1, databases, andtemporary files. The HDD 206 is exemplified as a storage of the imageforming apparatus, but may be a solid state disk (SSD).

The option unit 205 is an interface prepared for function enhancement,and is connected with a wireless communication unit for wirelesscommunication with a facsimile machine that transmits and receivesfacsimile data and a portable terminal such as a smart phone.

<Description About Power Source Control Configuration Block>

FIG. 3 is a block diagram illustrating a power source system of theimage forming apparatus 1 according to the first embodiment.

As illustrated in FIG. 3 , a standby power source 300 is connected to anexternal power source through the AC plug 100. The standby power source300 outputs power (standby power) while the AC plug 100 is connected tothe external power source. Even if the image forming apparatus 1 is inthe power-OFF mode, the standby power source 300 outputs power as longas the AC plug 100 is connected to the external power source. Thestandby power source 300 converts an AC voltage applied from theexternal power source into a DC voltage (AC-DC conversion), andgenerates a DC voltage of 12 V. The DC voltage output from the standbypower source 300 is applied to each unit (CPU 200, RAM 204, ROM 208, HDD206, network control unit 207, image processing unit 201, operation unit203, and option unit 205) connected to the standby power source 300.Needless to say, the DC voltage of 12 V generated by the standby powersource 300 is converted by a DC-DC converter (not illustrated), into avoltage appropriate for each unit (e.g., 5 V, 3.3 V, and 1.0 V).

When the power switch 105 is turned ON by the user with the AC plug 100being connected to the external power source, the power switch 105outputs a switch signal (output) 112 indicating a switch-ON state (highlevel). When the power switch 105 is turned OFF by the user with the ACplug 100 being connected to the external power source, the power switch105 outputs the switch signal 112 indicating a switch-OFF state (lowlevel). The level of the switch signal 112 corresponds to a state of thepower switch 105.

A voltage monitoring unit 301 monitors an output voltage from thestandby power source 300. The output voltage of the standby power source300 is applied to the voltage monitoring unit 301. The voltagemonitoring unit 301, which is a typical power source monitoringintegrated circuit (IC), can set delay time using an external capacitor.When the output voltage from the standby power source 300 exceeds athreshold voltage Vth and delay time Td set using the external capacitorhas elapsed, the voltage monitoring unit 301 brings a voltage detectionsignal 320 to a high impedance state. When the output voltage is belowthe threshold voltage Vth, the voltage monitoring unit 301 brings thevoltage detection signal 320 to the low level. The threshold voltage Vthis, for example, a voltage (e.g., 8.5 V) that is lower than a ratedoutput voltage (12 V) of the standby power source 300 and higher than aguaranteed operation voltage (3.3 V) of the CPU 200.

An AND unit 302 outputs a logical AND output 321 of the switch signal112 from the power switch 105 and the voltage detection signal 320 fromthe voltage monitoring unit 301. The logical AND 321 is output to thepower control unit 202 and an OR unit 303. Turning ON the power switch105 by the user causes the AND unit 302 to turn ON a switch 304 throughthe OR unit 303. Turning OFF the power switch 105 by the user causes theAND unit 302 to notify the power control unit 202 of the turning OFF ofthe power switch 105. The AND unit 302 may be composed of, for example,an AND gate element. When the voltage monitoring unit 301 is of an opencollector output type, the AND unit 302 may be configured by connectingthe output terminal of the power switch 105 with the voltage monitoringunit 301 via a resistor through pattern connection (wired ANDconnection).

The OR unit 303 outputs a logical OR output 323 of the logical ANDoutput 321 from the AND unit 302 and a control signal 322 from the powercontrol unit 202. The control signal 322 is a signal to maintain an ONstate of the switch 304 when the power switch 105 is turned OFF by theuser, and keep supplying power to the power control unit 202. The ORunit 303 may be configured of an OR gate element or may be configured byconnecting open collector output type elements through patternconnection (wired OR connection).

The circuit composed of the AND unit 302 and the OR unit 303, to which asignal from the power switch 105 and a signal from the voltagemonitoring unit 301 are input, functions as a signal output unit foroutputting the logical OR output 323.

The switch 304 is a switch that is controlled by the logical OR output323 from the OR unit 303 and that supplies power generated by thestandby power source 300 to the power control unit 202 and the like. Thepower supplied through the switch 304 is converted by the DC-DCconverter (not illustrated), into a voltage required for the powercontrol unit 202 and supplied to the power control unit 202.

The power control unit 202 communicates with the CPU 200 through aplurality of communication signals 326 including an interrupt signal, toturn ON/OFF the switch 304, a switch 305, a switch 306, and a switch 307in response to an instruction from the CPU 200.

The switch 305 is a switch to supply power generated by the standbypower source 300 to the CPU 200, the RAM 204, and the ROM 208. Theswitch 305 is turned ON/OFF based on a power source control signal 324output from the power control unit 202. The switch 306 is a switch tosupply power generated by the standby power source 300 to the networkcontrol unit 207. The switch 306 is turned ON/OFF based on a powersource control signal 325 output from the power control unit 202. Theswitch 307 is a switch to supply power generated by the standby powersource 300 to the HDD 206, the image processing unit 201, the operationunit 203, and the option unit 205. The switch 307 is turned ON/OFF basedon a power source control signal 327 output from the power control unit202.

A main power source 308 is connected to the external power sourcethrough the AC plug 100. The main power source 308 converts an ACvoltage received from the external power source to a DC voltage (AC-DCconversion), and generates a DC voltage of 24 V. The DC voltage outputfrom the main power source 308 is applied to each unit (printer unit 103and scanner unit 104) connected to the main power source 308. Needlessto say, the DC voltage of 24 V generated by the main power source 308 isconverted by the DC-DC converter or the like (not illustrated) to avoltage appropriate for each unit (e.g., 12 V, 5 V, and 3.3 V). Theswitch 106 is a switch to supply power to the printer unit 103. Theswitch 106 is turned ON/OFF based on a power source control signal 114output from the power control unit 202. The switch 107 is a switch tosupply power to the scanner unit 104. The switch 107 is turned ON/OFFbased on a power source control signal 115 output from the power controlunit 202.

In the normal power mode, each switch illustrated in FIG. 3 is turnedON. With this operation, power is supplied to each unit illustrated inFIG. 3 .

In the sleep mode, the output from the main power source 308 is stopped.When the sleep mode shift condition is satisfied, the power control unit202 controls the activation signal 113 to stop the output from the mainpower source 308. When the output from the main power source 308 isstopped, the supply of power to the printer unit 103 and the scannerunit 104 is stopped. When the sleep mode shift condition is satisfied,the power control unit 202 controls the power source control signal 327to turn OFF the switch 307. With this operation, the supply of power tothe HDD 206, the image processing unit 201, the operation unit 203, andthe option unit 205 is stopped.

In the power-OFF mode, the supply of power to each unit illustrated inFIG. 3 is stopped. Even in the power-OFF mode, the standby power source300 supplies power to the voltage monitoring unit 301.

<Description About Operation of Power Source Control ConfigurationBlock>

FIGS. 4 to 6 are timing charts of the signals according to the firstembodiment.

FIG. 4 is a timing chart illustrating operations performed when thepower switch 105 is turned ON with the AC plug 100 being connected tothe external power source.

When sufficient time has elapsed since the connection of the AC plug 100to the external power source, an output voltage from the standby powersource 300 stabilizes. When the output voltage from the standby powersource 300 exceeds the threshold voltage Vth, the voltage detectionsignal 320 becomes high level. Turning ON the power switch 105 in astate of the voltage detection signal 320 being in the high level bringsthe switch signal 112 from the power switch 105 to a high level. Whenboth the voltage detection signal 320 and the switch signal 112 becomethe high level, the logical AND output 321 from the AND unit 302 and thepower source control signal 324 from the OR unit 303 also become thehigh level. This operation turns ON the switch 304, thereby supplyingpower output from the standby power source 300 to the power control unit202.

When power is supplied to the power control unit 202, the power controlunit 202 brings the power source control signal 324 to the high level,thereby turning ON the switch 305. With this operation, power issupplied to the CPU 200, the RAM 204, and the ROM 208. When power issupplied to the CPU 200, the RAM 204, and the ROM 208, the CPU 200 loadsa program stored in the ROM 208 and starts to operate. When startingoperation, the CPU 200 communicates with the power control unit 202through the communication signal 326. The power control unit 202, basedon the communication with the CPU 200, brings the power source controlsignal 325 to the high level and turns ON the switch 306 to supply powerto the network control unit 207. When power is supplied to the networkcontrol unit 207, the CPU 200 initializes communication with the networkcontrol unit 207 to start communicating with the network control unit207. Subsequently, the CPU 200 brings the power source control signal327 to the high level, thereby turning ON the switch 307. With thisoperation, power is supplied to the HDD 206, the image processing unit201, the operation unit 203, and the option unit 205.

Further, the power control unit 202 brings the power source controlsignals 114 and 115 to the high level based on the communication withthe CPU 200. When the power source control signal 114 and 115 arebrought to the high level, the switches 106 and 107 are turned ON. Withthis operation, power is supplied to the printer unit 103 and thescanner unit 104. When supplied with power, the printer unit 103, forexample, drives a motor for a fixing unit, drives a motor for a polygonmirror, and warms up the fixing unit. When supplied with power, thescanner unit 104, for example, turns ON light emitting diodes (LEDs) ofa contact image sensor (CIS), and determines a home position of ascanning head. When these operations are completed, the image formingapparatus 1 shifts to the standby state.

Until the image forming apparatus 1 shifts to the standby state, the CPU200 brings the control signal 322 to the high level through the powercontrol unit 202.

FIG. 5 is a timing chart illustrating signals output when the powerswitch 105 is turned OFF.

Turning OFF the power switch 105 with the image forming apparatus 1being in the standby state brings the switch signal 112 from the powerswitch 105 to the low level. Thus, the logical AND output 321 from theAND unit 302 is also brought to the low level. Even if the logical ANDoutput 321 from the AND unit 302 becomes low level, the control signal322 remains at the high level, so that the logical OR output 323 fromthe OR unit 303 remains at the high level and the switch 304 remains ON.

When the output 321 from the AND unit 302 becomes low level, the powercontrol unit 202 communicates with the CPU 200 through the communicationsignal 326. When notified of the turning-OFF of the power switch 105,the CPU 200 executes shutdown processing. The shutdown processingincludes termination processing of software executed by the CPU 200(application software and operating system) and closing processing of afile. The shutdown processing further includes store processing ofcontents of the RAM 204 to the HDD 206, cache flush of the HDD,retraction of the HDD head, and processing to store setting valuesregarding image processing stored in the image processing unit 201 tothe nonvolatile area. The operation unit 203 displays that the shutdownprocessing is being performed. The shutdown processing includestermination processing of the communication by the option unit.

When the CPU 200 starts the shutdown processing, the printer unit 103,for example, releases pressing by the fixing unit and separates aprimary transfer unit based on an instruction from the CPU 200. Further,the scanner unit 104, for example, moves the scanner head to the homeposition. When the shutdown processing is completed, the power controlunit 202 brings the power source control signals 114 and 115 to the lowlevel based on an instruction from the CPU 200. With this operation, theswitches 106 and 107 are turned OFF, thereby stopping the supply ofpower to the printer unit 103 and the scanner unit 104. Further, thepower control unit 202 brings the power source control signal 327 to thelow level, thereby stopping the supply of power to the HDD 206, theimage processing unit 201, the operation unit 203, and the option unit205.

Further, the CPU 200 resets the network control unit 207 so that thesupply of power to the network control unit 207 can be interrupted. Thepower control unit 202 brings the power source control signal 325 to thelow level to stop the supply of power to the network control unit 207.

When various processing executed by the CPU 200 is completed, the powercontrol unit 202 brings the power source control signal 324 to the lowlevel, thereby stopping the supply of power to the CPU 200, the RAM 204,and the ROM 208. Further, the power control unit 202 checks a level ofthe logical AND output 321 from the AND unit 302. When it is the lowlevel, the power control unit 202 brings the control signal 322 to thelow level. With this operation, the switch 304 is turned OFF.Consequently, the supply of power to the power control unit 202 isstopped and the image forming apparatus 1 shifts to the power-OFF mode.

FIG. 6 is a timing chart illustrating operations performed when theoutput voltage from the standby power source 300 is reduced andsubsequently the output voltage is recovered.

When an output voltage 110 from the standby power source 300 is reducedto be lower than the threshold voltage Vth when the image formingapparatus 1 is in the standby state, the voltage monitoring unit 301brings the voltage detection signal 320 to the low level. When thevoltage detection signal 320 becomes low level, the logical AND output321 from the AND unit 302 becomes low level. When the logical AND output321 from the AND unit 302 becomes low level, the power control unit 202communicates with the CPU 200 through the communication signal 326. Whennotified of the turning-OFF of the power switch 105, the CPU 200executes shutdown processing. The shutdown processing to be executed atthis time is the same as the shutdown processing executed when the powerswitch 105 is turned OFF, but is not necessarily identical completely.

Subsequently, when the output voltage 110 from the standby power source300 is recovered and exceeds the threshold voltage Vth, the voltagemonitoring unit 301 maintains the low level of the logical AND output321 until the delay time TD that is set using the external capacitorelapses. A threshold voltage used to determine whether the outputvoltage 110 is recovered may be different from the threshold voltage Vthused to determine whether the output voltage stabilizes.

When the shutdown processing is completed, the power control unit 202checks the level of the logical AND output 321 from the AND unit 302. Ifit is determined to be the low level, the power control unit 202 causesthe control signal 322 to be low level. With this operation, the switch304 is turned OFF. Consequently, the supply of power to the powercontrol unit 202 is stopped and the image forming apparatus 1 shifts tothe power-OFF mode.

When the delay time Td set to the voltage monitoring unit 301 haselapsed, the voltage detection signal 320 becomes high level.Subsequently, in the same activation sequence as that when the powerswitch 105 is turned ON described with reference to FIG. 4 , the supplyof power to each unit of the image forming apparatus 1 is resumed, andthe image forming apparatus 1 shifts to the standby state.

<Advantageous Effect of First Embodiment>

According to the first embodiment, even if the output voltage from thestandby power source 300 is reduced, the shutdown processing of theimage forming apparatus 1 can be executed. In this way, software can beappropriately terminated. Further, the contents in the RAM 204 can bestored in the HDD 206 and the cache flush of the HDD can be executed, sothat a loss of data can be prevented. Furthermore, setting valuesregarding image processing can be stored in a nonvolatile area, so thata loss of the setting values can be prevented. In addition, the head ofthe HDD can be retracted, so that the head can be prevented fromaffecting a disk.

Furthermore, according to the first embodiment, when the output voltagefrom the standby power source 300 is recovered, the image formingapparatus 1 can be activated without operating the power switch by theuser. This operation can prevent the image forming apparatus 1 fromremaining in the power-OFF mode for a while despite the recovery of thepower source. With this operation, for example, the facsimile machinecan be prevented from remaining in a state of being unable to receivefacsimile data.

<Description About Power Source Control Configuration Block>

FIG. 7 is a block diagram illustrating a power source system of an imageforming apparatus according to a second embodiment.

According to the second embodiment, an AND unit 702 corresponding to theAND unit 302 of the first embodiment and an OR unit 703 corresponding tothe OR unit 303 of the first embodiment are incorporated in a powercontrol unit 704. Incorporating the AND unit 702 and the OR unit 703 inthe power control unit 704 can reduce the number of parts.

Other Embodiments

Embodiment(s) of the present disclosure can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While various embodiments have been described, it is to be understoodthat the invention is not limited to the disclosed embodiments. Thescope of the following claims is to be accorded the broadestinterpretation so as to encompass all such modifications and equivalentstructures and functions.

What is claimed is:
 1. An electronic apparatus, comprising: a mechanismto maintain ON and OFF as power states; a power source; a powermonitoring circuit configured to monitor an output voltage from thepower source; a power controller configured to control power supply fromthe power source; and a processor configured to output a signal to thepower controller based on receiving signal inputs from the mechanism andthe power monitoring circuit and that operates using power output fromthe power source, the processor being configured to: execute activatingprocessing and shutdown processing on the electronic apparatus based onthe signal input from the mechanism; execute the activating processingand the shutdown processing on the electronic apparatus based on thesignal input from the power monitoring circuit; execute the shutdownprocessing on the electronic apparatus based on the monitored voltagefalling below a first threshold even if the mechanism maintains an ONstate; and based on the monitored voltage rising above a secondthreshold while the mechanism maintains the ON state from when theshutdown processing is executed, execute the activation processing onthe electronic apparatus.
 2. The electronic apparatus according to claim1, wherein the first threshold is equal to the second threshold.
 3. Theelectronic apparatus according to claim 1, wherein the power sourceincludes an alternating current (AC) to a direct current (DC) converter.4. The electronic apparatus according to claim 1, wherein the powersource is a standby power source configured to output standby power. 5.The electronic apparatus according to claim 1, wherein the power sourceis configured to supply power to the processor.
 6. The electronicapparatus according to claim 1, wherein the processor is configured toexecute the activation processing on the electronic apparatus based on apredetermined time having elapsed since the monitored voltage has risenabove the threshold.
 7. The electronic apparatus according to claim 6,wherein the predetermined time is set to be longer than a duration forcompleting the shutdown processing.
 8. The electronic apparatusaccording to claim 1, wherein the mechanism is a power switch.
 9. Theelectronic apparatus according to claim 8, wherein a state maintained bythe power switch is changed to an OFF state in a case where the powerswitch that maintains an ON state receives a user operation, and a statemaintained by the power switch is changed to the ON state in a casewhere the power switch that maintains the OFF state receives a useroperation.
 10. The electronic apparatus according to claim 8, whereinthe processor outputs a signal to the power controller on a conditionthat the processor receives inputs from both the power switch and thepower monitoring circuit.
 11. The electronic apparatus according toclaim 1, further comprising a storage, wherein the storage is a harddisk or a solid state disk (SSD).
 12. The electronic apparatus accordingto claim 1, wherein the power source does not stop outputting powerwhile a DC voltage is supplied to the power source through a plug. 13.The electronic apparatus according to claim 1, further comprising aprinter configured to print an image on a recording medium.
 14. Theelectronic apparatus according to claim 1, further comprising a readerconfigured to read an original document image.
 15. The electronicapparatus according to claim 1, wherein the processor is configured to:execute the activation processing on the electronic apparatus if themonitored voltage rises above the second threshold in the electronicapparatus on which the shutdown processing, based on the monitoredvoltage falling below the first threshold, has been executed, and notexecute the activation processing on the electronic apparatus if themonitored voltage rises above the second threshold in the electronicapparatus on which the shutdown processing has been executed, theshutdown processing executed based on a user operation for turning offthe electronic apparatus.
 16. The electronic apparatus according toclaim 1, wherein the processor is configured to: based on the monitoredvoltage rising above the second threshold, execute the activationprocessing on the electronic apparatus on which the shutdown processing,based on the monitored voltage having fallen below the first threshold,has been executed, and even if the monitored voltage rises above thesecond threshold, not execute the activation processing to theelectronic apparatus on which the shutdown processing has been executed,the shutdown processing executed based on a user operation for turningoff the electronic apparatus.
 17. The electronic apparatus according toclaim 1, wherein the shutdown processing includes movement of data froma volatile storage device to a non-volatile storage device.
 18. Ashutdown method of an electronic apparatus, wherein the electronicapparatus includes a mechanism to maintain ON and OFF as power states, apower source and a power monitoring circuit, the power source supplyingpower to a processor, a power monitoring circuit configured to monitoran output voltage from the power source, a power controller configuredto control power supply from the power source, a processor configured tooutput a signal to the power controller based on receiving signal inputsfrom the mechanism and the power monitoring circuit, the shutdown methodcomprising: executing activating processing and shutdown processing onthe electronic apparatus based on the signal input from the mechanism;executing the activating processing and the shutdown processing on theelectronic apparatus based on the signal input from the power monitoringcircuit; executing the shutdown processing on the electronic apparatusbased on the monitored voltage falling below a first threshold even ifthe mechanism maintains an ON state; and based on the monitored voltagerising above a second threshold while the mechanism maintains an ONstate from when the shutdown processing is executed, executing theactivation processing to the electronic apparatus.